This invention relates to halo orthoses, and, more particularly, to an apparatus and method for exactly constraining patients"" heads within halo orthoses.
A halo orthosis minimizes motion of the cervical spine after traumatic injury or in recovery after surgery. To immobilize the cervical spine, the halo orthosis provides a rigid structure that fixes the head of the patient relative to the patient""s chest. The standard halo orthosis includes a crown or halo ring and halo pins that secure the halo ring to the head of the patient. The basic design of the halo orthosis has changed very little since its introduction in 1959.
Two of the most common problems associated with halo orthoses are pin loosening and/or pin migration (hereinafter referred to jointly and severally as xe2x80x9cpin looseningxe2x80x9d). To ensure that the head is properly fixed, the halo pins typically must pierce through the skin and rest against or embed in the skull. However, bone remodeling at the pin sites, changes in the elasticity of the head or skull, and/or other physiological changes in the head or skull geometry typically cause the pins to loosen over time. Proactive and/or corrective pin adjustments require undesirably complex and costly follow-up care by highly skilled medical professionals (typically orthopedic surgeons). For the patient, pin loosening can cause significant pain, potential loss of immobilization, and an increased risk of infection.
Indeed, infection is another common problem with halo orthoses. As the halo pins typically pierce the skin, each pin site creates a wound that is vulnerable to infection. Notwithstanding any loosening and/or retightening of the pins, the undesirably high number of pin sites in prior designs adds to the risk of infection.
The application procedures for prior halo orthoses also present problems. Historically, an orthopedic surgeon or team of orthopedic surgeons has been required to manually balance the torque among the various separate pins in order to properly apply the halo. Typically, such procedures are painful to the patient and require significant amounts of time and skill from the orthopedic surgeons.
Thus, there is a need for a halo orthosis that provides reduced pin loosening. Also, there is a need for a halo orthosis that requires a minimal number of pin sites. Additionally, there is a need for a halo orthosis that requires less time and skill to apply.
The present invention provides an apparatus for restricting movement of a patient""s head. The apparatus includes a frame and a plurality of constraints engaged with the frame to exactly constrain the patient""s head relative to the frame.
In one embodiment, the plurality of constraints includes a first constraint engaged with the frame to permit exactly three degrees of motion of the patient""s head relative to the frame, a second constraint engaged with the frame to permit exactly four degrees of motion of the patient""s head relative to the frame, and a third constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame.
In an alternative embodiment, the plurality of constraints includes a first constraint engaged with the frame to permit exactly four degrees of motion of the patient""s head relative to the frame, a second constraint engaged with the frame to permit exactly four degrees of motion of the patient""s head relative to the frame, and a third constraint engaged with the frame to permit exactly four degrees of motion of the patient""s head relative to the frame.
In another alternative embodiment, the plurality of constraints includes a first constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a second constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a third constraint engaged with the frame to permit exactly four degrees of motion of the patient""s head relative to the frame, and a fourth constraint engaged with the frame to permit exactly four degrees of motion of the patient""s head relative to the frame.
In another alternative embodiment, the plurality of constraints includes a first constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a second constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a third constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, and a fourth constraint engaged with the frame to permit exactly three degrees of motion of the patient""s head relative to the frame.
In another alternative embodiment, the plurality of constraints includes a first constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a second constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a third constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a fourth constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, and a fifth constraint engaged with the frame to permit exactly four degrees of motion of the patient""s head relative to the frame.
In another alternative embodiment, the plurality of constraints includes a first constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a second constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a third constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, a fourth constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, and a fifth constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame, and a sixth constraint engaged with the frame to permit exactly five degrees of motion of the patient""s head relative to the frame.
In yet another alternative embodiment, the present invention provides a method for restricting movement of a head of a patient with a frame and a plurality of constraints. The method includes the step of exactly constraining the head relative to the frame.
The features and advantages of the present invention described above, as well as additional features and advantages, will be readily apparent to those skilled in the art upon reference to the following detailed description and the accompanying drawings.